Given the native American trends in the assassin's clothing my feel is that he's going to be neutral in the war, and/or both parties are going to be made to look as bad as the other. 3 parties warring over items of Eden sounds plausible to me.

If the Pieces of Eden were created by the 'First Civilization' and in this world are pieces of religious (Or simply crazy as in the case of the Crystals Skulls, which don't ask me why are apparently Pieces of Eden) significance such as the Apple, Excalibur, the Ankh, Shroud of Turin etc. then why is the Declaration of Independence a Piece of Eden? Unless they do some weird wibbly wobbly timey wimey stuff then it can't work as the Pieces of Eden were created by the 'First Civilization' whereas the Declaration of Independence wasn't itself created until 1776 which if the extinction of the 'First Civilization' and the loss of the knowledge of how to make Pieces of Eden is to be believed then it can't possibly work within the framework of their own story.

And even if it was, the first few games of the series have used images from a variety of time periods to show 'hidden' messages in them. My take is that this stuff stretches across a rather large expanse of time.

And even if it was, the first few games of the series have used images from a variety of time periods to show 'hidden' messages in them. My take is that this stuff stretches across a rather large expanse of time.

This is my understanding as well. At least, that's what I got from all of Subject 16's puzzles in AC2.

If the Pieces of Eden were created by the 'First Civilization' and in this world are pieces of religious significance such as the Apple, Excalibur, the Ankh, Shroud of Turin etc. then why is the Declaration of Independence a Piece of Eden?

Becauese Uhmurica was the first country! You must be a commie if'n you don know it.